Systems and methods herein generally relate to registration (alignment) of stacks of sheets, and more particularly to reducing paper sliding on compiler shelves to promote proper registration.
Many modern production devices output sheets of media, such as sheets of paper, transparencies, plastic sheets, ceramic sheets, metallic sheets, etc. These sheets are often output into stacks, and the stacks are more efficiently processed if all the sheets are aligned with each other. For example, many printing devices align a stack of sheets before stapling the stack.
Some compiling strategies send the lead edge of paper into the throat of a stapler. In front of the stapler, there is a narrow shelf (e.g., a compiler shelf) that helps guide the paper into the stapler and then provides support for the front portion of the paper as it begins to accumulate. The majority of the sheet body is then dropped onto the stack of previously compiled sets. The top of the stack, however, is located approximately below the narrow shelf and staplers (necessary for ejecting the newly compiled set onto the stack). This height delta can cause sheets to “walk downhill” as additional sheets are compiled, creating angled, poorly registered sets. Furthermore, this delta grows larger as small, stapled sets develop staple build-up.